Growth and nutrition of normal fullterm infants from birth to 8 months of age is being studied by a variety of approaches. Daily intakes of food are determined and measurements of length, weight, skinfold thickness and serum biochemical parameters are made at regular intervals. Specially prepared, ready-to-feed formulas are employed. Certain of the investigations include metabolic balance studies. Representative studies concern (1) factors that influence food intake by infants (e.g., caloric density of food, percentage of calories supplied from fat, sweetness of the food), (2) 24-hour energy expenditures by normal infants, (3) requirements for protein and essential amino acids, (4) digestibility of various fats, (5) digestibility of starch, (6) effect of protein intake on urinary excretion of calcium, (7) requirements for zinc, (8) the influence of consuming whole milk on gastrointestinal blood loss.